Technological method for treating 2-hydroxy-benzonitril wastewater

Abstract

The invention discloses a technological method for treating 2-hydroxy-benzonitril wastewater. The technological method specifically comprises the following steps: firstly, transferring wastewater produced by refining 2-hydroxy-benzonitril into a distillation kettle; evaporating to remove acidic low-boiling residues and then evaporating to remove a large part of water, wherein the water can be used for refining the 2-hydroxy-benzonitril; secondly, transferring high-concentration saline water into a crystallization kettle and evaporating and crystalizing; centrifuging to obtain a byproduct sodium chloride, wherein the purity of the byproduct reaches 98 percent, wherein the water obtained by centrifuging can be used for refining the 2-hydroxy-benzonitril. The byproduct can be offered for sale so that the wastewater treatment cost is saved; the design of the technological method for treating the 2-hydroxy-benzonitril wastewater is optimized and requirements on the design of the technological method for treating the 2-hydroxy-benzonitril wastewater are met.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a process for treating salicylonitrile wastewater. Background technique [0002] Salicylonitrile, Chinese alias: o-hydroxybenzonitrile; 2-cyanophenol; 2-hydroxybenzonitrile; o-hydroxybenzonitrile; o-cyanophenol, physical and chemical properties: crystallization; ), boiling point 149°C / 1.9kPa (14mmHg) off-white powdery solid, very pungent smell, a small amount can affect people's breathing, and the smell is bitter; if a small amount of salicylonitrile is opened in the state of no ventilation, the smell can be It quickly spreads throughout the room; therefore, protective measures must be taken during operation to reduce the irritation to the respiratory tract; it is used as an intermediate for the organic synthesis of Bunirolol and an intermediate for the fungicide azoxystrobin. [0003] Salicylonitrile is an important intermediate in the organic synthesis of Bunirolo...

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Problems solved by technology

[0006] 1. The waste water after salicylonitrile synthesis, which is directly transported to the company's sewage treatment plant for direct treatment without workshop treatment, contains a lot of acidic low boiling substances, such as hydrogen chloride, thionyl chloride and phosphorus trichloride, which are produced in water A large number of toxic substances seriously affect the water quality;

[0007] 2. The waste water after salicylonitrile synthesis, which is directly transported to the company's sewage treatment plant for direct treatment without workshop treatment, contains more acidic low boiling substances, such as hydrogen chloride, thionyl chloride and phosphorus trichloride, which can corrode, Destroy the production equipment of the company's sewage treatment plant, which is not conducive to production and treatment;

[0008] 3. The waste water synthesized by salicylonitrile, which is directly transported to the company's sewage treatment plant for direct treatment without workshop treatment, contains sodium chloride that can be recycled. The sodium chloride obtained by distillation and crystallization has a purity of 98%, which can Selling as a by-product saves the cost of wastewater treatment, but it is directly sent to the sewage treatment plant for treatment, which cannot effectively recover the by-product and seriously damages the economy.

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